Improvement in steam safety-valves



@uiten gieten atnt @frn E. MEGGENHOFEN, OF ."RANKFOR'I ON TIIE MAIN, GER-MANY, ADMINIS- TRATRIX OF THE ESTATE OF EDWARD MEGGENHOFEN, DEGEASED. zetter-s Patent No. 65,25%, dated' Ill'ag/ 28, 1867.

IMPROVEMENT IN STEAM SAFETY-VALVES.

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TO ALL WHOM IT MAY CONCERN:

Be it known that E. MEGGENHOFEN, deceased, late of Frankfort on the Main, Germany, during his lifetime did invent a new and useful improved Spring-Balance; and I, Mrs. E. MEGGENHOFEN, adniinistratrix of the estate of said MEGGENHOFEN, do hereby declare that the following is a full, clear, and exact description thereof, which will enable those skilled in the' art to make and use the saine, reference being had to the accompanying drawing, forming part of this specication, in which drawing- Figure 1 represents a front elevation of this invention.

Figure 2 is a side elevation of the saine, showing` its position when the safety-valve is closed.

Figure 8 is a similar view of the same, showing its position when the safety-valve is half open.

Figure 4 is a similar` view of the saine, showingits position when the safety-valve is fully open.

Similar letters indicate corresponding' parts.

. This invention relates to a spring-balance for steam boilers, in which the connection between the valvelever and the spring Ais eiected by a combination of levers which are so proportioned that the downward pressure exerted on the valve-lever remains unchanged by the rising of the valve and consequent increase of the tension of the spring, and that a spring-balance'is obtained which, when applied to a safety-valve, works as correct as a weight.4 If a spring-balance of the ordinary construction is applied to a safety-valve, the downward-pressure exerted by the same on the valve increases considerably as the valve rises, and the steam does not escape through the valveA opening with the maximum pressure for which the valve is set, but with a much higher pressure, whereby the correct action and the object of the safety-valve are defeated. This defect is avoided by th'e arrangement which forms the subject-matter of this present application for a patent.

y A represents the spring-balance, or the shell which cncloses the spring.v This balance is secured to the i steam boiler by two lugs, B', which are secured to the boiler, and which are bored out to receive the gudgeons projecting from the cross-head B, through which. the stein of the spring-balance passes, as shown in the drawing. This stem is provided with n. screw-thread to receive the nuts I, by which the tension of the spring` is adjusted according to the pressure at which the valve is to blow oit. From the upper end of the valve extends an arm, E, which foi-uisl the bearing forthe fulcrum-pin, 6, of thebell-crank lever, C, and this bell-crank lever is con neeted at one end to the pendent rod, F, which is secured to the valve-lever G, while the other end of said bell-` crank lever connects by a rod, D, with the cross-head E. The end of the rod F passes through the valve-lever, and it is provided with a screw-thread and nut, I-I, whereby the spring-balance can be adjusted in the desired position. The arm E and the rod F are curved, so that when the valve is down the bea-ring points of tho crosshead B, the pivots c and Z1, and the connection c of the valve-lever with the rod F, will be in one and the same plane, as indicated by a line drawn through these points in iig. 2. If the valveY rises the tension of the .spring increases, and the spring-balance assumes the position shown in igs. 3 and 4, according to the distance to which the valve is permitted to open, but in all these positions the points B, c, and e, will remain in the same plane which coincides with the direction in which the strain takes place. 'At the same timel` when the valve opens the spring-balance is thrown out of its vertical position, and when the valve is half open the points a assume theposition shown in iig. 3, and when the valve is fully open said points assume .the position shown in iig. 4, and the tension of the spring increases. For instance, if the spring-balance is originally to 8O pounds pressure, and the proportion of the valve, valve-lever, and spring-balance is as shown in iig. 3 of the drawing, the spring draws out to correspond to a pressure of 1120 pounds, or nearly so, it' the valve is half opened, and'it draws out to correspond to a pressure of 140 pounds, or nearly so, if the valve is fully opened. This discrepancy in the i amount of pressure is counteracted by the bell-crank lever C, the arras of which are so proportioned that if the original pressure to which the spring-balance is set is equal to Q, and the increase occasioned by the lifting of 7 the valve equal to q, the result, QXy, is always equal to the result (Q X g) a', where the line y represents the length of a perpendicular line drawn from the point a on the line D c c, and the line a: the length oi a perpendicular line drawn from the point a on the line D Z1, these lines :c and y representing the length of the levers on which the strain acts. For instance, let the length of the arm Z1 c be equal to l inches, that of the arm (t 6x4-g inches, and the valveflcver und spring-balance so proportioned 'that when the valve is halt` opened the spring,r

will be extended 2%- inches, equal to an increase inthe pressure of 40 pounds; then the length of the line x will be 4%; inches, and that of the line y=633 inches, which gives 80 X 636=120 X42; But if the valve is fully opened the spring is extended 3% inches, equal to an increase in the pressure of 60 pounds, and thelength of the line a; is inches, und that of the line y equal to Egg;- 'ncl1es, which gives again 80X 6g140 3 By these means the power exerted bythe spring ontho valve remains uniform, no matter what the position of the valve may be, and the valve closes as soon as thc pressure of. the steam sinks below the desired point.

What I claim as new, and desire to secure by Letters Patent, is The arrangement of the bell-crank lever C, connecting-rod D, with reference to the svpring-halnnce A, constructed substantially as and for the purpose set forth. i

The above specification signed by me this 30th day of January, 1867. v

E. MEGGENI-IOFEN. Witnesses:

AUGUST GLOEP, GEORGE LXNK. 

